On 16/09/10 23:34, Paul Eggert wrote:
> On 09/16/10 11:21, Eric Blake wrote:
>> document -m, with --block-size=M as the long-option spelling
>> add -g, with --block-size=G as the long-option spelling
>
> This doesn't sound like a good idea. Multi-terabyte disks
> are already here, and "df -t" is already taken. Also,
> "df -g" already means something different in Solaris.
>
> Is it really that hard to type "df -Bg"?
Yes I agree the current unit selection options are fine.
> If we're going to make incompatible changes, I suggest that
> we solve the problem once and for all, by having "df" choose
> the default blocksize dynamically, based on the size of the
> output line describing the smallest disk. For example, where
> "df" currently outputs this:
>
> Filesystem 1K-blocks Used Available Use% Mounted on
> /dev/sda1 11620338002 1437021 11618900981 1% /r/opt
> /dev/sda2 20971520 1335871 19635650 7% /home/eggert
>
> "df" would notice that the smallest file system is between 1GB and 1TB,
> so it would default to 1 GB blocks, as follows:
>
> Filesystem 1GB-blocks Used Available Use% Mounted on
> /dev/sda1 11900GB 2GB 11898GB 1% /r/opt
> /dev/sda2 22GB 2GB 21GB 7% /home/eggert
>
> This is much more useful as an output format, because one can visually
> see which file systems are larger by seeing how many digits are there.
> Contrast this to the output of df --si:
>
> Filesystem Size Used Avail Use% Mounted on
> /dev/sda1 12T 1.5G 12T 1% /r/opt
> /dev/sda2 22G 1.4G 21G 7% /home/eggert
>
> which is harder to visually parse that way.
That would break lots of scripts I'd say
(they should use -P, but many don't).
In any case I don't think there is enough benefit
in such a format change given the common wide range
of device sizes attached to systems.
Personally I find the `df -h` format easiest to read.
> While we're at it, we should fix "df" so that its columns line up better;
> that would be another incompatible change, but it'd be worth it
> on hosts where the file system names are long.
We definitely should do this to support languages
with side column headings, and `df -B\'1`
I've an unfinished local branch to do this with mbsalign()
cheers,
Pádraig.